Problem #4 (Reflection and Absorption losses) For many of these problems, you may need to look up the index of refraction or absorption coefficient for silicon and silicon-nitride (hint: PVCDROM, Appendices). You may assume that the absorption for a thin SiN layer is negligible. Please cite all sources. a) For 600 nm light (near the peak of the solar spectrum), what percentage of light is reflected off the front surface of a polished silicon wafer? b) If SiN is used as anti-reflection coating (ARC) what thickness should be used if we optimize for 600 nm light? c) If we assume only one pass of light through the silicon, estimate the thickness required to absorb 90% of incident, non-reflected photons at 600 nm? Calculate the same for 1000 nm light? Which one will need thicker material